DATA REDUCTION FOR KAPPA AND ALPHA FROM TRANSIENT HEATING OF SLAB

For the transient heat conduction of a thin slab, the temperature-time history of its mid-point can be determined from a plane wall theory, provided that a slab thickness to length ratio of 0.2 or smaller is us ed in the experiments. Using the theory, two data reduction methods ar e described for deducing the thermal properties of conductivity (k) an d diffusivity (alpha) simultaneously from a single transient heating e xperiment. The first method uses an analytical technique to fit the in flection point on the temperature-square root(t) history plot to the t heoretical inflection point. The second method, which was earlier prop osed by the authors, uses a statistical curve fitting procedure to obt ain the best fit between theory and experiment over seven points on th e temperature-time history. Comparisons of the k values obtained by th ese methods against steady-state heat conduction measurements of the s ame slabs for various building construction materials indicate good ag reement, and give support to the validity of these procedures. The val ues of k and alpha obtained by these procedures also compare favourabl y with reported literature data.